The NFL playoffs are finally upon us. Here are six things to watch -- three for each of Saturday's wild card games -- as the postseason battles begin:

Kansas City Chiefs at Indianapolis Colts, 4:35 p.m. ET

1. Charles in charge

Kansas City running back Jamaal Charles finished the regular season as the NFL's third-leading rusher, topping the AFC with 1,287 yards despite sitting out last week's season finale against the Chargers. Perhaps the most versatile running back in the league, Charles also leads the Chiefs in receptions (70) and receiving yards (693) and scored a league-high 19 touchdowns this season. In short, he makes the Chiefs' offense go.

When the Colts beat the Chiefs 23-7 in Kansas City two weeks ago, Charles finished with 144 yards of total offense and averaged 8.2 yards per carry. His 106 yards on the ground could have been much more if not for the Colts offense, which built a double-digit lead early in the second half to give notoriously pass-happy Chiefs coach Andy Reid an excuse to take to the air.

Indianapolis can't count on the offense taking the ball out of Charles' hands again this time around. The Colts defense will need to find a way to corral the playmaking tailback and force Kansas City quarterback Alex Smith to beat them.

2. Pressing their Luck

Kansas City Chiefs outside linebacker Justin Houston (50) during the first half of an NFL football game against the San Diego Chargers at Arrowhead Stadium in Kansas City, Mo., Sunday, Nov. 24, 2013. (AP Photo/Ed Zurga)

The Colts' offensive line -- a unit devoid of Pro Bowl players -- has allowed the sixth-fewest sacks in the NFL this season, but that doesn't mean second-year quarterback Andrew Luck hasn't taken a heap of punishment. Only two teams have allowed more than the 107 quarterback hits surrendered by Indianapolis this season.

While the Kansas City pass rush isn't as fearsome as it was early in the season, the Chiefs still tied for sixth in the NFL with 47 sacks. Linebacker Justin Houston, who collected 11 sacks in the season's first eight games, will return to the lineup today after missing the last five weeks with a dislocated elbow, reuniting with Tamba Hali (11 sacks) and Dontari Poe (4.5) on the Kansas City defensive line.

Like all young quarterbacks, Luck still has a tendency to get rattled by pressure. In the five games this season in which he was sacked three or more times, Luck committed a total of six turnovers -- the same number he had in the Colts' 11 other games combined. If the Chiefs' pass rush can return to form today with Houston back in the fold, game-changing turnovers could follow.

3. Riding the momentum

A lack of momentum heading into the postseason isn't an issue for a team with a clear-cut talent advantage or a roster hardened by playoff experience. The Chiefs have neither, and their second-half slump could prove costly.

After a surprise 9-0 start, Kansas City went just 2-5 after the bye week with their only wins coming against the 3-13 Redskins and the 4-12 Raiders. Indianapolis, by contrast, enters the playoffs on a three-game winning streak and playing perhaps its best football of the season.

Will that disparity play into the equation here? The Colts are playing in front of their home crowd with the confidence that comes from knowing that they hammered this Chiefs team just two weeks ago in Kansas City. The Chiefs have Andy Reid's steady hand on the wheel and some veteran players, like Alex Smith, who know how to win in the playoffs, but the psychological toll of falling from the top of the NFL to the AFC's fifth seed in seven weeks could prove too big a hurdle. If the Colts start fast today, this one could be over quickly.

How do you stop a 6-foot-7, 265-pound tight end who runs the 40-yard dash in 4.5 seconds? You don't, which is why Jimmy Graham caught 86 passes for 1,215 yards and 16 touchdowns this season.

For the Eagles, there isn't even an obvious answer for slowing down the Saints' dynamic tight end. The Eagles' defense is weakest up the middle, which is where Graham does some of his best work. Who can Philly use in coverage who would have any chance?

Mychal Kendricks is a talented young linebacker with sub-4.5 speed, but he's been a step behind opposing tight ends all season. At 6-foot-4, Connor Barwin has the size to do the job, but isn't fast enough to go vertical with Graham. The Eagles' safeties -- Nate Allen, Patrick Chung and rookie Earl Wolff -- are average at best.

In their last two games, the Eagles surrendered a combined 17 catches and 220 yards to tight ends Martellus Bennett of the Bears and Jason Witten of the Cowboys. Neither is Jimmy Graham. The Eagles' only hope may be to get to Saints quarterback Drew Brees before he can get the ball to his favorite target. If they can't, Graham's night will resemble his signature touchdown celebration: a slam dunk.

2. Shady dealings

Philadelphia Eagles' LeSean McCoy rushes during the first half of an NFL football game against the Chicago Bears Sunday, Dec. 22, 2013, in Philadelphia. (AP Photo/Matt Rourke)

The Eagles defense won't be the only unit dealing with an unstoppable force. The Saints will face an equally lethal foe in Eagles running back LeSean McCoy. McCoy's Twitter account is @CutonDime25 -- and it's an apt handle. The man they call Shady led the NFL with 1,607 yards rushing this season, breaking defenders' ankles and earning comparisons to Barry Sanders along the way.

While New Orleans ranks fourth in total defense under new defensive coordinator Rob Ryan, his unit has been inconsistent against the run. The Saints held the likes of San Francisco's Frank Gore and Seattle's Marshawn Lynch under 50 yards rushing, but were gouged by the Buccaneers' Doug Martin (144), the Jets' Chris Ivory (139) and the Ram's Zac Stacy (133).

Unless the Saints are willing to risk being burned by Nick Foles and a potent Eagles passing attack, consistently committing an extra defender to stopping the run isn't an attractive option. That means New Orleans will have to win the one-on-one battles against perhaps the NFL's most athletic offensive line if it hopes to shut down McCoy.

3. Feeling Domesick

Stop me if you've heard this already, but the Saints don't play nearly as well on the road as they do at the Superdome. They're a perfect 8-0 in New Orleans this season, but just 3-5 in games played outside the Big Easy.

Brees, in particular, doesn't seem to have the same juice. The statistical difference between home games (73.6 completion percentage, 27 TDs, 3 INTs and a sterling 126.3 passer rating) and road games (64 percent, 12 TDs, 9 INTs, 84.8 rating) is glaring.

It's unlikely the Philly faithful will make it any easier on the Saints themselves. Tickets to the game sold out in minutes, despite the frigid forecast. The Saints will face not only the wrath of the fans, but also bitter-cold weather with game-time temperatures expected to be in the 20s.